Nd∶YAG激光加氟化钙对牙本质小管的阻塞作用

Combined occluding effect of calcium fluoride varnish and Nd∶YAG laser irradiation on human dentinal tubules in vitro

目的 通过离体牙实验 ,评价Nd∶YAG激光和氟化钙一起作用于牙本质表面对牙本质小管的阻塞效果。方法 选择四颗恒牙 ,随机分组后 ,制成四个 1 5mm厚的牙片。每张牙片又分为实验区和对照区 ,激光照射牙本质和正常牙本质。实验区牙本质涂布氟化钙 ,再用Nd∶YAG激光照射 ;对照区只用激光照射。用扫描电镜观察被照射后牙本质超微结构的变化。结果 正常牙本质有无数暴露的牙本质小管口 ;对照区牙本质小管大部分被关闭 ,有部分牙本质泡状结构和球形突起 ;实验区牙本质小管口完全关闭 ,表面平坦 ,无球形突起和裂纹出现。随着照射能量的上升 ,牙本质熔融程度和熔融深度增加 ,但产生小裂纹的机会也增加。结论 Nd∶YAG激光和氟化钙联合照射牙本质 ,可以补充丢失的钙质和氟元素 ,牙本质熔融完善 ,表面平坦 。

Objective To evaluate the combined occluding effect of calcium fluoride varnish and Nd∶YAG laser irradiation on human dentinal tubules in vitro . Methods Four human intact teeth were made into 4 dentinal slices of 1.5 mm thickness and divided into 2 groups. Each slice was divided into two areas, one as experimental area and another as control. Experimental area was varnished with calcium fluoride and lased with Nd∶YAG laser, the control region was only lased by laser. Dentinal ultrastructure was observed with scanning electron microscopy (SEM). Results Dentin in non irradiated region showed many exposed dentinal tubule orifices, while dentin in control manifested foam like structures with some ball like protrusion and the tubule orifices were closed mostly,whereas, dentinal orifices in experimental area were closed completely, and no ball like protrusion and cracks was found. The more lased energy increased, the more the melted degree and depth of dentin reached, but cracks occurred accordingly. Conclusion If Nd∶YAG laser and calcium fluoride are combined to apply on hypersensitive dentinal surface, dentin will be melted more completely and plainly because calcium and fluoride element are complimented to dentin surface.